Natural gas may be transferred through pipes by land or sea, or may be liquefied and transferred to remote destinations using liquefied natural gas (LNG) carriers. LNG is obtained by cooling natural gas to a very low temperature (about −163° C.), such that the volume of LNG is about 1/600 of the volume before liquefaction. Thus, LNG may be easily transferred to remote destinations by sea.
Since LNG has a very low temperature and high pressure, the role of LNG storage tanks is important. In addition to being used in LNG carriers, such fluid storage tanks may also be used in LNG Floating, Production, Storage, and Offloading (FPSO) facilities for liquefying and storing produced natural gas at sea and transferring stored LNG to LNG carriers, or in LNG Floating Storage and Regasification Units (FSRUs) installed on the sea far from land for receiving LNG from LNG carries, regasifying the LNG, and supplying the regasified LNG to land destinations.
Recently, there have been attempts to use LNG as a fuel for various means of transportation such as ocean-going vessels. In this case, LNG is stored in cylindrical storage tanks. However, since cylindrical storage tanks are small, many cylindrical storage tanks may be required, and thus a relatively large space of a vessel may be required to allow cylindrical storage tanks to be arranged at predetermined intervals.